The XMLHttpRequestEventTarget.onloadstart
is the function called when an XMLHttpRequest
transaction starts transferring data.
Syntax
XMLHttpRequest.onloadstart = callback;
Values
callback
is the function to be called when the transaction begins to transfer data.
Example
var xmlhttp = new XMLHttpRequest(), method = 'GET', url = 'https://developer.mozilla.org/'; xmlhttp.open(method, url, true); xmlhttp.onloadstart = function () { console.log("Download underway"); }; xmlhttp.send();
Specifications
Specification | Status | Comment |
---|---|---|
XMLHttpRequest | Living Standard | WHATWG living standard |
Browser compatibility
The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.
Update compatibility data on GitHub
Desktop | Mobile | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Basic support | Chrome ? | Edge ? | Firefox ? | IE ? | Opera ? | Safari ? | WebView Android ? | Chrome Android ? | Edge Mobile ? | Firefox Android ? | Opera Android ? | Safari iOS ? | Samsung Internet Android ? |
Legend
- Compatibility unknown
- Compatibility unknown